In conventional information recording and reproducing devices, there has been commonly used, as disclosed in Japanese Patent Laid-Open No. 57010/2001, a method, in which a temperature sensor is used to sense an ambient temperature, feeding electric power to a CPU when the ambient temperature is low, raising temperature of an information recording and reproducing device by temperature rise of the CPU, starting up the information recording and reproducing device in a state, in which temperature of the information recording and reproducing device comes in a temperature range of certified level at the time of operation, and reversely using a cooling fan to cool the information recording and reproducing device when the ambient temperature is high.
Also, information recording and reproducing devices of the prior art are arranged and used in a room where air conditioning is complete.
Further, Japanese Patent Laid-Open No. 332049/2001 discloses a method of preventing fletching abrasion (abrasion of rolling surfaces caused by minute vibrations) of spindle bearings in a magnetic disk device of load/unload type. Concretely stated, with the devices of load/unload type, a slider is free from contacting with a disk and thereby stopping, and so when an external shock is applied, a spindle motor is placed under no restraint and increased in freedom of rotation to cause fletching abrasion. In order to prevent such fletching abrasion, an anti-adhesion film is coated on a slider or a CSS (Contact Start and Stop) zone is provided on a disk so that a slider is caused to contact with the disk and stop and freedom of rotation is placed under restraint through a disk when a spindle motor stops.
Recently, giving and receiving of information has been made in automobiles through the medium of satellites and other information equipments as adopted in on-board navigation systems or the like, and transmission and reception of mails are made possible from unspecified places by means of mobile telephone. In the future, an amount of information in such on-board navigation systems, mobile telephones or the like will be more and more increased, and the degree of necessity for information recording and reproducing devices for recording and reproducing such information has been more and more increased.
Hereupon, an information recording and reproducing device is loaded in an automobile whereby it becomes possible in a navigation system to make a high-speed response and update information at any time through the medium of satellites or the like and to make download of a large amount of information. Also, a large amount of information such as Internet or the like can be handled with an information recording and reproducing device loaded in an automobile.
Conventionally, it is general that the operating environment of an information recording and reproducing device is such that the device is placed in an air-conditioned room and mounted in a housing provided with a cooling fan to be free from vibrations from outside, and temperature of the operating environment is in the order of 0° C. to 50° C.
In contrast, with on-board information recording and reproducing devices, it is necessary to take into consideration that an interior of an automobile is raised to 100° C. when left under hot midsummer sky and lowered to −40° C. in cold districts, and it is demanded to operate normally under an environment in an automobile subjected to vibrations.
In particular, no consideration has been given to a phenomenon that micro-movement abrasion is caused in bearings used for rotational driving of a rotating section, in a state that, rotating sections of the information recording and reproducing devices, a spindle motor and a carriage, for example stop under an environment, in which such rotating section stops, under an environment, in which vibration is continuously applied to, the information recording and reproducing device, and therefore the rotational accuracy is rapidly degraded. Concretely stated, when vibration is applied from outside, balls continuously collide against inner and outer races in the case of ball bearings, and a shaft continuously collides against a hub in the case of fluid bearings.
The invention discloses a control mechanism, a control method and other related techniques, in which bearings in information recording and reproducing devices loaded on vehicles, for example, automobiles are prevented from internal abrasion and degradation in rotational accuracy is prevented.